Background:

Although intellectual disability (ID) is a common disability in Iran, there is no investigation on the spatial distribution pattern of these patients in national level and the spatial maps for recognition the areas with higher prevalence of IDs and local neighborhoods of these regions or effect of socio-demographic factor on this scattering is not still available. This proposition motivated us to assess the population with ID in our country.

Methods:

In a cross-sectional study, we applied Moran's Index (Moran's I) which includes information about the strength of the neighboring association between counties, as global univariate distribution assessment. A geographically weighted regression was used to explore relation between ID patient's prevalence and some socio-demographic factors (migration and illiteracy rate, physician number (PN)/10,000 people and health-care centers (HCCs)/10,000 people).

Results:

We found that spatial clusters of ID patients exist among Iran counties (Moran's I = 0.36, P < 0.01) and in a rural area population groups (Moran's I = 0.20, P < 0.01). Further, we detected spatial associations between ID patients and all of our investigated socio-demographic factors in national scale. In rural areas, illiteracy has high association with ID especially in the south region of Iran. Urban area has random pattern of ID patients both within and between the Iran counties (Moran's I = 0.01, P > 0.3).

Conclusions:

According to the results, our Initial hypothesis about the existence of spatial clusters in distribution of people with ID in Iran was proven. Spatial autocorrelation between migration and illiteracy rate and prevalence of patients with ID was shown and was in agreement with our hypothesis. However, our supposition that the prevalence should have inverse relationship with PN and HCC was rejected.